杭电ACM1001

 

//题目：http://acm.hdu.edu.cn/showproblem.php?pid=1000
//解答：ziqiao
#include<iostream>
#include<vector>
using namespace std;
void main()
{
    vector<int> a;
    int n;
    while(cin>>n)
    {
        int sum=0;
        for(int j=1;j<=n;j++)
            sum+=j;
        a.push_back(sum);
    }
    for(vector<int>::size_type ix=0; ix!=a.size();++ix)
        cout<<a[ix]<<endl<<endl;
}